Baby's sighs tied to breathing pattern

A baby's sweet sighs may do more than endear it to its parents - they may help reset regular breathing patterns and help lungs develop, researchers reported on Thursday.

Such deep breaths, which healthy babies take every 50 to 100 breaths, help reopen parts of the lung, especially tiny airways prone to collapse, the researchers said.

But the team at the University Children's Hospital in Bern, Switzerland, and in Perth, Australia, wanted to know if sighs did more.

They studied 25 healthy 1-month-old infants while they were sleeping in a crib or in a parent's arms, checking the heart rate and blood oxygen saturation as well as other breathing-related factors.

Writing in the Journal of Applied Physiology, David Baldwin and colleagues said they found that sighs are a mechanism for improving the neurological control of breathing.

Just before a sigh, an infant's breathing becomes just a bit too regular, they said. The sigh adds some healthy variability to the breathing pattern, they said.

They noted that sick and premature infants seem to sigh more often than healthier babies. They may be struggling to reset their systems.

It may be possible, the researchers said, to use breathing patterns to identify those premature infants who are most at risk for problems of abnormal breathing control, including sudden infant death syndrome - also known as SIDS, or crib death.